Cigarette filter assemblies may comprise sorbent materials, such as carbon. Filters adapted to be incorporated in a filter cigarette, may comprise, for example, particles or granules of carbon, such as activated carbon or activated charcoal and/or other sorbent materials, incorporated within porous media material, such as cellulose acetate tow, or in cavities between the porous media material.
To the extent that sorbent particles or fragments of sorbent particles could possibly be entrained in the gas stream, such as mainstream smoke, passing through the filter and issue through (i.e., breakthrough) the outlet end of the filter such as the mouth end of a cigarette, techniques to reduce the amount of sorbent particle breakthrough in the gas stream would be of interest.